1. Field of the Invention
The present invention relates, in general, to a short drop mechanism for a vehicle door, which allows a window glass of the vehicle door to slide up and down when the door is opened and closed and, more particularly, to a short drop mechanism for a vehicle door, which improves a vertical actuation timing of the window glass so as to improve a manipulating feature by a driver when manipulating the door to be opened and closed.
2. Description of Related Art
Generally, a vehicle door is provided with a window glass for securing a lateral view of a vehicle, and a weather strip made of rubber for soundproofing and waterproofing features.
A door has a conventionally used door structure in which a weather strip is fixed to a door frame so that a window glass is lodged into the weather strip when moving up and down. That is, in the door, the window glass and the weather strip are all installed on the door frame, so that, when the door is opened, the window glass and the weather strip are not separated from each other, but the weather strip surrounds the moved-up window glass, advantageously having waterproofing and soundproofing features.
Recently, according to door design such as two-door design, a frameless-type door structure is available for use. Such a frameless-type door structure should be such that a weather strip is fixed to a vehicle body and a window glass is fixed to a door, so that, when the door is opened, the window glass and the weather strip are separated from each other. Thus, the weather strip has a shape in which one side thereof is opened in order to prevent interference with the opening of the door, thereby having poor soundproofing and waterproofing features.
To solve these problems of poor soundproofing and waterproofing features, the weather strip is adapted such that, when a door is closed, the window glass is surrounded by the weather strip. However, in this case, when the door is opened, interference of the window glass with the weather strip occurs, degrading manipulating performance of the door when opening and closing.
In the meantime, in order to solve the problems with the frameless-type door structure, the short drop of a window glass has been recently adapted. The short drop performs a function that, when detecting a door-opening action, quickly lowers the window glass by a certain distance under the control of a drive motor for a vertical motion of the window glass, and when detecting a door-closing action, raises the window glass by the previously lowered distance.
Such a short drop function makes it possible to prevent the interference of the window glass with the weather strip when the door is opened and closed, to allow the weather strip to surround the window glass, improving the soundproofing and waterproofing problems, and to open and close the window glass by a predetermined amount so as to control the internal pressure inside of a vehicle, improving the opening and closing performance of a door.
However, a conventional short drop system is such that a short drop switch 2 is mounted to a vehicle body 3 so that, when a door 1 is opened and closed, the system detects ON/OFF of the switch so as to implement a short drop function. Specifically, in a door-closed state, the door comes into contact with the switch mounted to the vehicle body, allowing the switch to maintain an ON state, and in a door-opened state, the door moves out of the contact state with respect to the switch, rendering the switch to enter an OFF state, allowing the window glass to move down.
A conventional short drop system operates in the following sequential procedure: manipulation of a handle—unlocking of a latch—partial opening of a door—switch OFF—determination of a controller—actuation of a window motor—a downward motion of a window glass.
However, such a conventional short drop system has problems in that, when the door is opened before the activation of the short drop function, an interference of the window glass with the weather strip occurs, so that the weather strip is subjected to abrasion, or the manipulation performance of the door is degraded due to a repulsive force by the weather strip. Further, in the conventional system, since the short drop function is activated when the door is just opened, the manipulation performance of the door is further degraded.
Similar problems occur with the conventional short drop system because a short drop signal is received when the door is already opened.
Thus, there is a need to improve a short drop function such as the performance of manipulation, e.g. manipulation feeling, quality or the like, by completely separating a door opening period and a short drop activating time.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information finals the prior art already known to a person skilled in the art.